MSUD is a potentially deadly disorder that affects the way the body breaks down three amino acids, leucine, isoleucine, and valine. When they're not being used to build a protein, these three amino acids can either be recycled or broken down and used for energy. They are normally broken down by six proteins that act as a team and form a complex called BCKD (branched-chain alpha-ketoacid dehydrogenase).
What causes MSUD?
People with MSUD have a mutation that results in a deficiency for one of the 6 proteins that make up this complex. Therefore, they can't break down leucine, isoleucine, and valine. They end up with dangerously high levels of these amino acids in their blood, causing the rapid degeneration of brain cells and death if left untreated.There is a classic form of MSUD and several less common forms. Each form varies in its severity and characteristic features. However, all subtypes of the disorder can be caused by mutations in any of the 6 genes used to build the BCKD protein complex.
SYMPTOMS
A baby who has the disorder may appear normal at birth. But within three to four days, the symptoms appear. These may include: loss of appetite, fussiness, and sweet-smelling urine. The elevated levels of amino acids in the urine generate the smell, which is reminiscent of maple syrup. This is how MSUD got its name. If left untreated, the condition usually worsens. The baby will have seizures, go into a coma, and die within the first few months of life.
GENETIC BACKGROUND
MSUD is inherited in an autosomal recessive pattern. For a child to get the disease, he or she must inherit a defective copy of the gene from each parent. If both parents carry the MSUD gene, each of their children has a 25 percent chance of getting the disorder, and a 50 percent chance of being a carrier.
BY : JAMES CAMPBELL
What is MSUD?
MSUD is a potentially deadly disorder that affects the way the body breaks down three amino acids, leucine, isoleucine, and valine. When they're not being used to build a protein, these three amino acids can either be recycled or broken down and used for energy. They are normally broken down by six proteins that act as a team and form a complex called BCKD (branched-chain alpha-ketoacid dehydrogenase).
What causes MSUD?
People with MSUD have a mutation that results in a deficiency for one of the 6 proteins that make up this complex. Therefore, they can't break down leucine, isoleucine, and valine. They end up with dangerously high levels of these amino acids in their blood, causing the rapid degeneration of brain cells and death if left untreated.There is a classic form of MSUD and several less common forms. Each form varies in its severity and characteristic features. However, all subtypes of the disorder can be caused by mutations in any of the 6 genes used to build the BCKD protein complex.
SYMPTOMS
A baby who has the disorder may appear normal at birth. But within three to four days, the symptoms appear. These may include: loss of appetite, fussiness, and sweet-smelling urine. The elevated levels of amino acids in the urine generate the smell, which is reminiscent of maple syrup. This is how MSUD got its name. If left untreated, the condition usually worsens. The baby will have seizures, go into a coma, and die within the first few months of life.
GENETIC BACKGROUND
MSUD is inherited in an autosomal recessive pattern. For a child to get the disease, he or she must inherit a defective copy of the gene from each parent. If both parents carry the MSUD gene, each of their children has a 25 percent chance of getting the disorder, and a 50 percent chance of being a carrier.